drm/xe/hwmon: Remove unwanted write permission for currN_label

Change umode of currN_label from 0644 to 0444 as write permission
not needed for label.

Signed-off-by: Karthik Poosa <karthik.poosa@intel.com>
Reviewed-by: Riana Tauro <riana.tauro@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419125945.4085629-1-karthik.poosa@intel.com


Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>